The CHECKER2 program, shown in Figure 4-6, is the same as CHECKER1 except that it includes a keyboard interface. You can use the Left, Right, Up, and Down arrow keys to move the cursor among the 25 rectangles. The Home key sends the cursor to the upper left rectangle; the End key drops it down to the lower right rectangle. Both the Spacebar and Enter keys toggle the X mark.
CHECKER2.MAK
#------------------------
# CHECKER2.MAK make file
#------------------------
checker2.exe : checker2.obj checker2.def
link checker2, /align:16, NUL, /nod slibcew libw, checker2
rc checker2.exe
checker2.obj : checker2.c
cl -c -Gsw -Ow -W2 -Zp checker2.c
CHECKER2.C
/*-------------------------------------------------
CHECKER2.C -- Mouse Hit-Test Demo Program No. 2
(c) Charles Petzold, 1990
-------------------------------------------------*/
#include <windows.h>
#define DIVISIONS 5
long FAR PASCAL WndProc (HWND, WORD, WORD, LONG) ;
int PASCAL WinMain (HANDLE hInstance, HANDLE hPrevInstance,
LPSTR lpszCmdLine, int nCmdShow)
{
static char szAppName[] = "Checker2" ;
HWND hwnd ;
MSG msg ;
WNDCLASS wndclass ;
if (!hPrevInstance)
{
wndclass.style = CS_HREDRAW | CS_VREDRAW ;
wndclass.lpfnWndProc = WndProc ;
wndclass.cbClsExtra = 0 ;
wndclass.cbWndExtra = 0 ;
wndclass.hInstance = hInstance ;
wndclass.hIcon = NULL ;
wndclass.hCursor = LoadCursor (NULL, IDC_ARROW) ;
wndclass.hbrBackground = GetStockObject (WHITE_BRUSH) ;
wndclass.lpszMenuName = NULL ;
wndclass.lpszClassName = szAppName ;
RegisterClass (&wndclass) ;
}
hwnd = CreateWindow (szAppName, "Checker2 Mouse Hit-Test Demo",
WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, CW_USEDEFAULT,
CW_USEDEFAULT, CW_USEDEFAULT,
NULL, NULL, hInstance, NULL) ;
ShowWindow (hwnd, nCmdShow) ;
UpdateWindow (hwnd) ;
while (GetMessage (&msg, NULL, 0, 0))
{
TranslateMessage (&msg) ;
DispatchMessage (&msg) ;
}
return msg.wParam ;
}
long FAR PASCAL WndProc (HWND hwnd, WORD message, WORD wParam, LONG lParam)
{
static BOOL fState[DIVISIONS][DIVISIONS] ;
static short cxBlock, cyBlock ;
HDC hdc ;
PAINTSTRUCT ps ;
POINT point ;
RECT rect ;
short x, y ;
switch (message)
{
case WM_SIZE :
cxBlock = LOWORD (lParam) / DIVISIONS ;
cyBlock = HIWORD (lParam) / DIVISIONS ;
return 0 ;
case WM_SETFOCUS :
ShowCursor (TRUE) ;
return 0 ;
case WM_KILLFOCUS :
ShowCursor (FALSE) ;
return 0 ;
case WM_KEYDOWN :
GetCursorPos (&point) ;
ScreenToClient (hwnd, &point) ;
x = max (0, min (DIVISIONS - 1, point.x / cxBlock)) ;
y = max (0, min (DIVISIONS - 1, point.y / cyBlock)) ;
switch (wParam)
{
case VK_UP :
y-- ;
break ;
case VK_DOWN :
y++ ;
break ;
case VK_LEFT :
x-- ;
break ;
case VK_RIGHT :
x++ ;
break ;
case VK_HOME :
x = y = 0 ;
break ;
case VK_END :
x = y = DIVISIONS - 1 ;
break ;
case VK_RETURN :
case VK_SPACE :
SendMessage (hwnd, WM_LBUTTONDOWN, MK_LBUTTON,
MAKELONG (x * cxBlock, y * cyBlock)) ;
break ;
}
x = (x + DIVISIONS) % DIVISIONS ;
y = (y + DIVISIONS) % DIVISIONS ;
point.x = x * cxBlock + cxBlock / 2 ;
point.y = y * cyBlock + cyBlock / 2 ;
ClientToScreen (hwnd, &point) ;
SetCursorPos (point.x, point.y) ;
return 0 ;
case WM_LBUTTONDOWN :
x = LOWORD (lParam) / cxBlock ;
y = HIWORD (lParam) / cyBlock ;
if (x < DIVISIONS && y < DIVISIONS)
{
fState[x][y] ^= 1 ;
rect.left = x * cxBlock ;
rect.top = y * cyBlock ;
rect.right = (x + 1) * cxBlock ;
rect.bottom = (y + 1) * cyBlock ;
InvalidateRect (hwnd, &rect, FALSE) ;
}
else
MessageBeep (0) ;
return 0 ;
case WM_PAINT :
hdc = BeginPaint (hwnd, &ps) ;
for (x = 0 ; x < DIVISIONS ; x++)
for (y = 0 ; y < DIVISIONS ; y++)
{
Rectangle (hdc, x * cxBlock, y * cyBlock,
(x + 1) * cxBlock, (y + 1) * cyBlock) ;
if (fState [x][y])
{
MoveTo (hdc, x * cxBlock, y * cyBlock) ;
LineTo (hdc, (x+1) * cxBlock, (y+1) * cyBlock) ;
MoveTo (hdc, x * cxBlock, (y+1) * cyBlock) ;
LineTo (hdc, (x+1) * cxBlock, y * cyBlock) ;
}
}
EndPaint (hwnd, &ps) ;
return 0 ;
case WM_DESTROY :
PostQuitMessage (0) ;
return 0 ;
}
return DefWindowProc (hwnd, message, wParam, lParam) ;
}
CHECKER2.DEF
;-------------------------------------
; CHECKER2.DEF module definition file
;-------------------------------------
NAME CHECKER2
DESCRIPTION 'Mouse Hit-Test Demo Program No. 2 (c) Charles Petzold, 1990'
EXETYPE WINDOWS
STUB 'WINSTUB.EXE'
CODE PRELOAD MOVEABLE DISCARDABLE
DATA PRELOAD MOVEABLE MULTIPLE
HEAPSIZE 1024
STACKSIZE 8192
EXPORTS WndProc
The WM_KEYDOWN logic in CHECKER2 determines the position of the cursor (GetCursorPos), converts the screen coordinates to client-area coordinates (ScreenToClient), and divides the coordinates by the width and height of the rectangular block. This produces x and y values that indicate the position of the rectangle in the 5-by-5 array. The mouse cursor may or may not be in the client area when a key is pressed, so x and y must be passed through the WINDOWS.H min and max macros to ensure that they range from 0 through 4.
For arrow keys, CHECKER2 increments or decrements x and y appropriately. If the key is the Enter key (VK_RETURN) or Spacebar (VK_SPACE), CHECKER2 uses SendMessage to send a WM_LBUTTONDOWN message to itself. This technique is similar to the method used in the SYSMETS program in Chapter 3 to add a keyboard interface to the window scroll bar. The WM_KEYDOWN logic finishes by calculating client-area coordinates that point to the center of the rectangle, converting to screen coordinates (ClientToScreen), and setting the cursor position (SetCursorPos).